Apparatus for cleaning walls



C. K. PERKINS APPARATUS FOR CLEANING WALLS Filed June 8, 1933 March 26, 1935.

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INVENTOR wnmassas Wad,

Patented Mar. 26, 1935 UNITED STATES PATENT OFFICE 16 Claims.

The invention relates to a method and apparatus for cleaning walls, ceilings, and the like. The cleaning of soiled wall-paper has been done in substantially the same way for a great many years, no improvements of any note having been-made during that time. The method most generally used, and which has hitherto been recognized as the best, comprises simply manually stroking or rubbing a soiled surface in one direction with a handful of doughy cleaning compound. The compound must first be thoroughly kneaded to make it soft and plastic. Then, after each stroke over the wall, the dirt and dust gathered by the compound must be kneaded into it to prevent the dirt from falling off or from smearing the wall on the next stroke. This preliminary and continual kneading consumes considerable time and effort, which tires the hands and sometimes makes them sore.

Furthermore, throughout the cleaning operation the cleaning compound crumbles and drops on the floor and furnishings. If walked on, it smears the floor and shoes and is tracked throughout the house. This crumbling is especially annoying when ceilings are being cleaned, because the crumbs fall on everything in the room, including the hair, face and eyes of the worker. In addition, particles of dirt and cleaner adhere to the walls and ceiling from which they must be carefully brushed in order to prevent streaking. 4

Another disadvantage of this time-honored cleaning method is that it depends to a very great extent upon the human element, which, of course, varies. That is, it is practically impossible in stroking walls with material held in the hand to apply uniform pressure and to clean in paths of uniform width throughout the cleaning operation. The result is streaks, misses, mars and improperly cleaned areas, all of which are displeasing in appearance and highly undesirable.

Finally, the principle of this method of cleaning is wrong, because the same wad of compound is continuously used until it becomes so saturated with dirt that it will pick up no more. Obviously, satisfactory cleaning can not be done with a dirty cleaning compound. On the other hand, it would be very difiicult, if not impossible, to so manipulate the compound in the hand during each stroke as to continuously bring an unsoiled portion of it into contact with the wall. It would also be too expensive to discard soiled compound at the end of each stroke, because a handful is required for making a satisfactory stroke.

Another method of cleaning, but one which is even less efficient than the one just described, is performed by stroking wall-paper with sponge rubber. Sponge rubber will pick up a substantial portion of dirt from a wall, but it alsorubs some of it into the paper, after which that dirt can never be removed. The rubber also crumbles as much as, if not more than, the plastic compound.

Both of these methods are messy and unsanitary, because dirt from the walls is in constant contact with the hands.

It is among the objects of this invention to provide a method for cleaning walls and the like in which wall-cleaning material does not contact with a wall after the material has become soiled; in which but little time and effort is required, and no dirt nor cleaning material is dropped; in which substantially all dirt isremoved without damaging the wall; and in which the cleaning material need never be touched by the hands.

It is also among the objects of this invention to provide a wall-cleaning machine for carrying out the above objects, which is light in weight, easily manipulatable, and sturdy; which continuously applies unsoiled wall-cleaning material to a wall, and simultaneously removes soiled material from further contact with the wall; which cleans evenly and thoroughly without damaging the wall; and which keeps the cleaning material out of contact with the hands.

Further objects are to provide a wall-cleaning material for use with this machine which does not crumble, which picks up substantially all of the dirt and retains it, and which is inexpensive to produce.

An embodiment of the invention is illustrated in the accompanying drawings, of which Fig. 1 is a plan view of a wall-cleaning machine with its cleaning material partly broken away; Fig. 2 is a front view thereof with the front of the machine partly broken away also; Fig. 3 is a view of the left side of the machine, as viewed in Fig. 2, with the side mostly broken away; Fig. 4 is a view taken on the line IVIV of Fig. 2; Fig. 5 is a view taken on the line V-V of Fig. 1; Fig. 6 a plan View of a ribbon of cleaning material; and Fig. '7 a diagrammatic side view of the front end of the ribbon showing its structure.

Referring to the embodiment of the invention illustrated in the drawings, the body or housing of the wall-paper cleaning machine is preferably formed from a single sheet of metal, the ends of v which have been bent at right angles to its center portion to form a top 1 and parallel depending sides 2 and 3. Before bending, the sheet is stamped to give it a predetermined shape, to form predetermined openings and reinforcing flanges 4 and 5, and to provide it with outstruck bosses 25 which prevent the housing sides from scraping against a wall when the machine is being manipulated in a corner of a room. A tie plate 6, connected in any suitable manner to the bottom of the housing sides at their front ends, prevents them from spreading apart and also serves other purposes to be explained later. Flanges 5, at the back of the housing, are likewise connected to the sides to prevent their rear ends from spreading.

The housing is provided with four independently journalled wheels to permit it to be rolledover a flat surface, such as a wall or ceiling, in any direction. To prevent the wheels from marking a wall, they are provided with corrugated rubber tires 7.

The two front wheels, 8 and 9 in Fig. 2, are mounted on opposite ends of a shaft 10 journalled in bearings 11 and 12 which are attached to an integral upright extension 13 of the tie plate. Wheel 8 is rigidly mounted on the shaft with the inner end of its hub in contact with bearing 11, and with the outer end of the hub journalled in a flanged opening 14 in the lower front portion of housing side 2. Wheel 9 is similarly disposed in an opening 15 in the opposite side of the housing, but it is rotatably mounted on shaft 10 so that it can turn independently of wheel 8 in order to permit the machine to be moved in an arcuate path if desired, as well as to distribute the work equally between the two front wheels.

As shown in Fig. 5, one end of the hub of each rear wheel 16 is journalled in a flanged opening 17 in a side of the housing, the other end be ing journalled in a similar opening 18 in the lower end of a journal bracket 19. Each bracket is held in spaced relation with a housing side by integral outwardly extending ears 20 secured to the latter.

A handle 21 is joined at its ends to the upper ends of handle brackets 22 which are connected to the top of the housing.

In accordance with the invention, this machine cleans a soiled surface by means of cleaning material disposed in the housing, unsoiled material being continuously moved into cleaning relation with the soiled surface, and soiled material being simultaneously removed therefrom. In order to accomplish this, a supply of cleaning material in ribbon-like form is provided, the-ribbon 23 preferably being wound on a spool 24 journalled in the housing. The ribbon, which will be described more completely later, comprises a backing strip, such as paper or fabric, on one face of which is disposed a thin layer of plastic cleaning compound.

The spool has a core which connects its end flanges 26 and projects through them to form journals 2'7. Bearings for these journals are formed on the sides of the housing in the following manner. Referring to Fig. 3, an elongate guide member 28 extends upward from the bottom of each side to whose inner face it is connected. The upper portion of the guide member is arcuate in order to form one section 29 of a spool bearing. Facing this arcuate portion and adapted to cooperate with it to retain a spool journal between them is an arcuate portion 31 formed in a retaining lever 32. The lever is pivoted, at a point 33 adjacent its arcuate portion, to the housing side, the lower arm 34 of the lever extending below the bottom of the side, and the upper arm 36 projecting through a slot 37 in the top of the housing. A coil spring 38, attached to the housing and the lever's upper arm, biases arcuate portion 31 towards guide member 28 for holding a spool journal in the bearing thus formed so that the machine can be operated in any position, inverted or otherwise. I

When a spool of paper-cleaning ribbon is to be inserted in the housing, the housing is turned on end and the journal ends of the spools core are brought into contact with the outer ends of guide members 28 and retaining levers 32 where they are temporarily positioned by the outwardly extending lower arms 34 of the levers. By pressing on the spool flanges these lower arms are forced away from the guide members, thereby permitting the core ends to slide between the guide members and levers and to snap into place between the cooperating arcuate portion 29 and 31. To remove the spool, the projecting ends of the levers upper arms are moved towards the guide members while the machine is right side up, whereupon the lower arms are moved away from them, the bearing is opened, and the spool drops out.

A substantially upright cover or guide plate 39, having a backwardly curved upper portion spaced from the top of the housing, is detachably connected to the front of the housing betweenits sides. The front edge of the plate is gripped between upright flange 40 and upright tongues 40a integral with tie plate 6, while the rear edge of the guide plate is held in contact with the upper edge of the tie plate by offset depending tongues 39a sprung in front of the upright portion of the tie plate. Overlying each end of the guide plate and perpendicular thereto is a guide flange 41 that prevents ribbon 23, which is drawn from the spool over theplate and under the housing, from moving laterally out of its path. They also serve as guards for protecting the edges of the ribbon. The guide flanges may conveniently be formed integrally with the housing sides when the housing is originally stamped from a sheet of metal.

For pressing the lower portion of the cleaning ribbon into frictional engagement with a wall on which the wheels of the cleaning machine bear, an elongated resilient pressure pad 42 is connected to the bottom of tie plate 6 transversely of the housing. The ribbon passes between the outer face of the pad and the wall being cleaned. The pad is relatively narrow so that only a very small portion of the total length of the cleaning ribbon engages the wall at any given moment.

Although this pad may be made in various ways to give it resiliency, it is shown in Figs. 3 and 4 as being formed from several layers of rubber strips 43 whose longitudinal edges are turned back and joined to a metal plate 44 from which the central portion of the pad is spaced to give resiliency. The front of the pad plate is provided with a pair of integral spring tongues 46 which are bent upward and backward above it. These tongues frictionally engage loop portions 47 struck out from the bottom of the tie plate, whereby the pressure pad is detachably held in place. Thus, if the pad hardens or otherwise becomes unsatisfactory, it can be easily replaced by a new one.

The pad is of such thickness that when all four wheels of the machine are in contact'with a wall, the portion of the cleaning ribbon between the pad and wall is pressed against the wall with just the right amount of pressure for proper cleaning. In this way pressure of cleaning material upon a solid surface is maintained uniform throughout the cleaning operation. Furthermore, as the pad is resilient, the ribbon is permitted to pass over wall-paper blisters without injuring the paper, and the ribbon is also pressed into depressions and seams where the plastering has been uneven.

It is apparent from this construction that if the machine were moved forward over a wall or other flat surface, the frictional engagement of the plastic cleaning compound with the well would prevent the ribbon from sliding thereover, and, therefore, would move the ribbon relative to the housing and continuously unwind it from its spool as the machine was rolled along. In other words, there would be no relative movement between the ribbon and wall at their area of contact, and the ribbon .would all be unwound before the housing had travelled more than a few feet. Therefore, means is provided for restricting the movement of the ribbon, relative to the housing, to a speed below the linear speed of the housing. With the portion of the ribbon in contact with the wall moving over it more slowly than the machine as a whole, the ribbon rubs against the wall and picks up and absorbs dirt as the machine moves along.

The ribbon retarding means comprises a pair of cylindrical drums 48 mounted on opposite ends of a shaft 49. See Fig. 2. The shaft is jcurnaled in the ends of a horizontally disposed bracket 51 which is connected beneath the curved top of guide plate 39 to upward extension 13 of guide plate 6. On the shaft between the drums there is mounted a bevel pinion 53 which meshes with a smaller bevel pinion 54 mounted on the upper end of a vertical shaft 56. This latter shaft is journalled in an integral extension 5'7 of the horizontal bracket, and in an opening in the bottom of the tie plate. A worm wheel 59 is mounted on the lower end of the vertical shaft where it meshes with a worm 61 on front wheel shaft 10. Through this train of gears, front wheel 8, rigidly mounted on shaft 10, causes the drums to rotate much more slowly than the wheel does when the machine is moved over a wall.

Openings 62 are formed in the curved upper portion of the guide plate, and the drums are 50 disposed that portions of their surfaces lie substantially flush with the outer surface of that plate, whereby the under side of the cleaning ribbon engages them as it passes over the guide plate from spool 2d.

The relatively slow rate of rotation of the drums is transmitted to the ribbon, the linear speed of which is correspondingly reduced, by means of a plurality of spines or needles 63 projecting radially from the peripheries of the drums. These needles perforate the ribbon, or, preferably, enter preformed perforations in the paper backing strip, as it is pulled over the drums by its frictional engagement with a wall, whereby its movement is retarded and the ribbon is dragged or rubbed over the wall as the machine moves along. Retaining levers 32, pressing against the spool journals, hod the ribbon taut between the spool and drums, thereby holding the ribbon down on the drums with needles 63 projecting into it.

It is desirable and important that soiled ribbon, as it slowly but continuously moves from between the pressure pad and the wall, be taken care of to prevent it from coming in further contact with the wall. An efficient means for doing this is illustrated in the drawings, by the use of which the used or soiled portion of the ribbon is wound up in the housing simultaneously with the unwinding of the fresh or unsoiled portion. Accordingly, a wind-up shaft or tube 64 is mounted in the rear of the housing parallel to the supply spool. One end of this tube is rotatably mounted in an opening 65 in the upper portion of the journal bracket 19 behind front wheel 8, and is provided with a key 66. Housing side 2 adjacent the key is provided with an offset opening 67 in which the fingers may be inserted for turning the key. The key normally does not project from the housing. See Fig. 5.

The opposite end of the wind-up tube is provided with longitudinal slits 68 forming resilient prongs 69 which are bulged radially outward and which frictionally engage the inner surface of the hollow hub 71 of a toothed gear '72. The tube is prevented from working itself out of the gear by an inner annular shoulder 71a, as shown in Fig. 5, which abuts against the bu ged portion of spring prongs 69. However, if key 66 is pulled on, shoulder 7111 will force the prongs together, thereby permitting them to be drawn out of hub 71. The inner end of the hub is journalled in a flanged opening 73 in the upper end of the journal bracket 19 behind front wheel 9, the opposite end of the hub being journalled in a similar opening 74 in side 3 of the housing. The central portion of the tube is provided with a spring clip '76 adapted to clamp the front end of the cleaning ribbon against the tube. The end of the clip nearest key 66 is the end which is attached to the tube so that the ribbon will be released when the wind-up tube is pulled out of the housing.

In order to rotate gear 72, in which one end of the wind-up tube is frictionally engaged, a gear shaft 77 is journalled in brackets '78 fastened to the inner face of the housing side 3, as shown in Fig. 3. The rear end of this shaft is provided with a worm 79 which meshes with the wind-up shaft gear 72, and the opposite end of the shaft is provided with a small bevel pinion 81. Meshing with the latter is a larger bevel gear 82 having a toothed periphery and being journalled in the upper end of a vertically dis posed bracket 83 attached to upward extension 13 of tie plate 6. In the lower end of this bracket there is journalled a toothed gear 84 which meshes with the peripheral teeth of bevel gear 82 above it, and also meshes with a small gear 86 rigidly mounted on the hub of the loosely mounted front Wheel 9.

Consequently, when that wheel is rotated in passing over a wall, the wind-up tube is turned very slowly through the train of gears just described. The direction of rotation of the tube is such that the soiled face of the ribbon is wound on the inside of the roll where it can not be touched by the hands. As the diameter of the roll of soiled ribbon increases, the rotating windup tube will tend to exert a greater strain on the ribbon between the tube and the pressure pad, but the strain is prevented from becoming too great because spring prongs 69 of the wind-up tube slip circumferentially in the hollow hub of gear 72, thereby retarding the rate of rotation of the tube and roll.

The cleaning ribbon, as briefly mentioned before and as shown in Figs. 6 and 'l, is preferably formed from a backing strip of paper or fabric 91 on one side of which is disposed a thin layer of doughy or plastic cleaning compound 92 such as has heretofore been used in the hand method of wall-paper cleaning. To prevent the backing strip from reacting to the elements of the compound, the paper is waterproofed. This may advantageously be done by applying a coat of tacky waterproof material, such as waterproof enamel 93, to the compound side of it, the compound being applied to the strip before the tacky material hardens. The material thus serves as a waterproofer and as an adhesive. Enamel has the further attribute of not contracting or twisting the paper. The opposite side of the paper is coated with wax 94, or other suitable material, to prevent the ribbon from sticking together when rolled on a supply. spool, and to decrease friction between it and the guide plate and pressure pad. The wax also serves as a waterproofer to protect the outer face of the backing strip against the action of the cleaning compound which engages it when the ribbon is rolled on the spool.

The compound is not applied to the full length of the backing strip, a clear space or leader 96 being left at the front end, and a similar space or trailer 97 remaining at the rear end. The foremost end of the strip is doubled back and glued to itself to strengthen that end and to prevent it from binding upon the wind-up tube. The forward edge of this double portion is formed with a wind-up tab 98 adapted to be clamped between spring clip 76 and the wind-up tube for holding the ribbon on the tube when the latter first starts turning. Projecting from each side of the tab is a gummed sealing tab 99 perforated along its line of juncture with the wind-up tab. In a new spool of cleaning ribbon these gummed tabs adhere to the paper leader 96 over which they lie, thereby preventing the ribbon from unwinding until the wind-up tab has been pulled up to tear it away from them and free the end of the ribbon.

Leader 96 is of such length that the wind-up tab is securely gripped by spring clip '76 before any cleaning compound reaches the pressure pad. Consequently, there is no waste of compound at the start of the cleaning operation.

Trailer 97 at the other end of the strip serves a similar purpose at the end of the cleaning operation. That is, all of the compound can be used without the rear end of the ribbon being released from the spool. The rear edge of the trailer is provided with a tab 100 for entering a slot 101 in the spools core to aid in winding the ribbon thereon in the preparation of a supply of cleaning ribbon.

To guide the front edge of the compound between the pressure pad and wall so that the compound will not be pushed away from the paper strip, a narrow strip of paper or cellophane 102 is fastened across the paper leader with one edge overlying the front edge of the compound. The sides of both the leader and the trailer are slightly tapered toward their outer ends to facilitate rolling.

The outer or working face of the cleaning compound is corrugated, preferably in the form of intersecting ridges 103 forming between them diamond-shaped depressions 104 in which dirt can accumulate. A wider ridge or bead 106 is formed along each edge of the compound to prevent dirt from escaping from the sides of the ribbon and to strengthen its edges. The ridges break down to conform to seams and other irregularities in a wall, and give a diagonal sweeping action. The flexibility of the ribbon is not impaired by the compound, because the compound is corrugated.

Trailer 97 is provided with two slots 10'! slightly wider than the needle drums and in such position that when the last of the cleaning compound has passed between the pressure pad and wall they reach the drums where the needles project through them. In this way the needles are prevented from pulling trailing tab 100 from slot 101 in the spools core after all the cleaning compound has been used. The front end of these apertures may be tapered to provide a gradual cessation of engagement between the needles and ribbon.

After the cleaning machine has been removed from the wall the trailer can be wound up on the wind-up tube by turning key 66. The tube is then pulled out of the roll of soiled ribbon through opening 67 in housing side 2, spring clip 76 sliding off wind-up tab 98. Upon being released from the machine in this way, the roll can be discarded and the wind-up tube reinserted in wind-up gear 72. If the tube is slightly tapered toward its prong end, it will slip out of a roll of ribbon more easily.

The paper strip is preferably provided longitudinally thereof with two parallel paths of perforations 108 in such position that they are engageable by the needles of the needle drums. These perforations make it unnecessary for the needles to punch the paper, thereby eliminating the tendency of the needles to cause the ribbon to bulge along their paths of contact with it. By perforating the paper from its waxed side toward the compound side, projections are raised on the latter side which enter the compound and aid in holding it in place.

At suitable spaced intervals along the length of the ribbon, it is also provided with transverse perforations 109, whereby unused sections of the ribbon may be easily torn therefrom for the purpose of touching up corners or any other spots which the machine did not reach.

To operate this cleaning machine it is rolled back and forth over a wall, all four wheels bearing against the wall during the forward stroke only, which is the cleaning stroke. Application of uniform pressure on the cleaning ribbon is insured throughout the cleaning operation because the front wheels keep the pressure pad the same distance from the wall at all times. During the back stroke of the machine it is tilted on its back wheels to remove the ribbon and front wheels from the wall. With the front wheels idle, all moving parts which are operativeLv connected to them remain motionless likewise. Thus, the ribbon is unwound from its spool only during the cleaning forward stroke, and no soiled portions of the ribbon are fed back into engagement with the wall. Only unsoiled cleaning compound ever comes in contact with the wall. As the back wheels remain in contact with the wall throughout the cleaning operation, the machine is easy to guide and fast to use.

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention, and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and dey in said means, means for pressing a portion of the ribbon into frictional contact with said wall whereby the frictional engagement of said portion of the ribbon with the wall causes the ribbon to unwind from the roll as said movable means is moved across the wall, means for restricting said unwinding to a speed below the linear speed of said movable means to cause the cleaning material to rub against the wall, and means for continuously removing soiled cleaning material from further contact with the wall.

2. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled wall, a spool of wall cleaning ribbon journalled in the housing, means for pressing a portion of the ribbon into frictional contact with said wall whereby movement of the housing thereover unwinds the ribbon from the spool and moves it relative to the housing, means disposed in said housing for restricting said relative movement of the ribbon to a speed below that of the housing to cause the ribbon to rub against said soiled wall, a wind-up shaft journalled in the housing, and means for continuously rotating the shaft when the housing is moved over said wall to wind on the shaft the ribbon after it leaves the pressing means.

3. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled wall, a spool of wall-cleaning ribbon journalled in the housing, resilient means for pressing a portion of the ribbon into frictional contact with said wall whereby movement of the housing thereover unwinds the ribbon from the spool and moves it relative to the housing, means disposed in said housing for restricting said relative movement of the ribbon to a speed below that of the housing to cause the ribbon to rub against said soiled wall, a removable wind-up shaft journalled in the housing, and means actuated by the movement of said housing across said wall for rotating the shaft to wind on it the ribbon after it leaves the pressing means.

4. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled wall, a wheel journalled in the housing for bearing against the wall and for turning as the housing is moved across it, a spool of wall-cleaning ribbon j ournalled in the housing, meansfor pressing a portion of the ribbon into frictional contact with said wall whereby movement of the housing thereover unwinds the ribbon from the spool and moves it relative to the housing, means disposed in said housing for restricting said relative movement of the ribbon to a speed below that of the housing to cause the ribbon to rub against said soiled wall, a removable wind-up shaft journalled in the housing, means actuated by the rotation of said wheel for rotating the shaft to wind on it the ribbon after it leaves the pressing means, and a slip connection between said wheel and shaft to permit the peripheral speed of said shaft to be retarded by the ribbon as the diameter of the roll of ribbon being wound thereon increases.

5. A machine for cleaning walls, comprising a housing, a plurality of wheels journalled therein for bearing against a wall, a spool of wall-cleaning ribbon journalled in the housing, means for pressing a portion of the ribbon into uniform frictional contact with said wall whereby movement of the housing thereover unwinds the ribbon from the spool and draws it across the housing, means actuated by one of said wheels as it is rolled over said wall for restricting said unwinding movement to a speed below that of said housing movement to cause the ribbon to rub against said wall and clean it, a removable wind-up shaft journalled in the housing, and means actuated by the movement of one of said wheels for rotating the shaft to wind on it the ribbon after it leaves the pressing means.

-6. A machine for cleaning walls, comprising a housing, a plurality of wheels journalled therein for bearing against a wall, a spool of wall-cleaning ribbon journalled in the housing, means for pressing a portion of the ribbon into uniform frictional contact with said wall whereby movement of the housing thereover unwinds the ribbon from the spool and draws it across the housing, means actuated by one of said wheels as it is rolled over said wall for restricting said unwinding movement to a speed below that of said housing movement to cause the ribbon to rub against said wall and clean it, a removable windup shaft journalled in the housing, means actuated by the movement of one of said wheels for rotating the shaft to continuously wind on it soiled ribbon, and clutch means disposed between said shaft-rotating means and said shaft whereby the shaft slips relatively to said shaft-rotating means as the diameter of the roll of ribbon being wound thereon increases.

'7. A machine for cleaning walls, comprising a housing, a plurality of wheels independently journalled therein for bearing against a wall and spacing the housing therefrom, a spool of wallcleaning ribbon journalled in the housing, detachable resilient means connected to the housing for pressing a portion of the ribbon into frictional contact with said wall whereby movement of the housing thereover continuously unwinds the ribbon from the spool and draws it across the housing, means actuated by one of said wheels as it rotates for restricting said unwinding movement to a speed below that of said housing movement to cause the ribbon to rub against said wall and clean it, a longitudinally removable wind-up shaft journalled in the housing, means actuated by another of said wheels as it rotates for turning the shaft to wind on it the ribbon after it leaves the pressing means, said shaft having a frictional connection with its actuating means whereby the shaft is permitted to slip circumferentially relative to said actuating means as the diameter of the roll of ribbon being wound thereon increases.

8. A machine for cleaning walls, comprising the combination of a housing, a plurality of wheels independently journalled therein for bearing against a wall and spacing the housing therefrom, a spool of wall-cleaning ribbon journalledin the housing, detachable resilient means connected to the housing for pressing a portion of the ribbon into frictional contact with said wall whereby movement of the housing thereover continuously unwinds the ribbon from the spool and draws it across the resilient pressure means, a cylindrical drum journalled in the housing and provided with a plurality of needles projecting radially from its periphery, said ribbon passing over the drum in its passage from said spool to said resilient pressure means whereby the needles perforate the ribbon, speed-reducing gears operatively connecting one of said wheels to the drum whereby the drum restricts said unwinding movement to a speed below that of said housing to cause the ribbon to rub against said wall and clean it, a removable wind-up shaft journalled in the housing for receiving soiled ribbon from the pressure means, speed-reducing gears operatively connect.

ing another of said wheels to said shaft, and a frictional connection between the shaft and its speed-reducing gears whereby the shaft is permitted to slip circumferentially relative to said gears.

9.. A machine for cleaning walls, comprising a housing provided with means for supporting a supply of unused wall-cleaning ribbon, a presser carried by the housing for positioning a portion of said ribbon in frictional contact with a wall, and means for continuously moving said ribbon across said presser relative to the wall as the machine is moved across the wall whereby unused wall cleaning ribbon is continuously brought into rubbing engagement with said soiled wall and soiled ribbon is continuously removed from further contact therewith.

10. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled surface, means for spacing the housing a substantially fixed distance from said surface, a spool of wall-cleaning ribbon disposed in the housing, means connected to the housing adjacent said surface for pressing a portion of the ribbon into frictional contact with the surface with uniform pressure throughout the cleaning operation to unwind the ribbon from the spool, means for restricting said unwinding to a speed below the linear speed of said housing to cause the cleaning material to rub against said soiled surface, and means disposed in the housing for receiving and winding up soiled ribbon as fast as it leaves said pressing means.

11. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled surface, a spool disposed in said housing, a strip of flexible material wound on the spool, a layer of wall-cleaning compound mounted on said flexible material to form a wall-cleaning ribbon, means for pressing a portion of said ribbon into frictional contact with said surface to unwind the ribbon from the spool, means for restricting said unwinding to a speed below the linear speed of said housing, and a wind-up shaft journalled in said housing for simultaneously winding up soiled ribbon.

12. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled wall, a spool disposed in said housing, a strip of flexible material wound on the spool, a layer of wall cleaning compound secured to one side of said strip whereby a wall-cleaning ribbon is formed, a coating of non-adhesive material applied to the other side of the strip to prevent adjoining layers of the ribbon from sticking together on the spool, means for pressing a portion of said ribbon into frictional contact with said wall to unwind the ribbon from the spool, and means for restricting said unwinding to a speed below the linear speed of said housing to cause said ribbon to rub against the wall and clean it.

13. A machine for cleaning walls, comprising a housing adapted to be moved across a soiled surface, a spool disposed in the housing, a strip of flexible material wound on said spool, a layer of wall-cleaning compound mounted on said strip to form a wall-cleaning ribbon, means for pressing a portion of the ribbon into frictional contact with said surface to unwind the ribbon from the spool, means for restricting said unwinding to a speed below the linear speed of said housing, a wind-up shaft removably journalled in said housing for simultaneously winding up soiled ribbon, means connected to the wind-up shaft for detachably securing the forward end of said flexible strip, the forward end portion of the strip being stiffened to prevent it from binding on said shaft, and a protective tape attached to the forward end portion of the strip transversely thereof and overlying the forward end of said compound to prevent the compound from being pushed back when it first contacts with said soiled surface.

14. A machine for cleaning walls,,comprising a casing provided with means for supporting a supply of unused wall-cleaning ribbon, a presser carried by the casing for positioning a portion of the ribbon in frictional contact with a wall, means actuated by moving the machine over the wall for removing ribbon from said supply and across said presser relative to the wall, and means independent of said supply support for receiving soiled ribbon from the presser.

15. In a machine for cleaning walls, the combination with a housing, a spool of wall-cleaning ribbon disposed therein, and means for moving a portion of the ribbon into and out of frictional contact with said surface to clean it as the housing is moved across the surface, of a two-part bearing mounted on each side of the housing for receiving the ends of said spool, one of said parts being resiliently biased toward the other, and guide portions extending from the bearings to the bottom of said housing whereby said spool may be quickly guided and snapped into place in said bearings.

16. In a machine for cleaning walls, the combination with a housing, a spool of wall-cleaning ribbon disposed therein, and means for moving a portion of the ribbon into and out of frictional contact with said surface to clean it as the housing is moved across the surface, of a twopart bearing mounted on each side of the housing for receiving the ends of said spool, one of said parts being resiliently biased toward the other, and guide portions extending from the bearings to the bottom of said housing whereby said spool may be quickly guided and snapped into place in said bearings, said resiliently biased parts being provided with extensions projecting above the housing for manually opening the bearings to release the spool therefrom.-

CECIL K. PERKINS. 

